TABLE 1.
Kinetics of fluoroquinolone transport by quiescent and PMA-activated neutrophilsa
| Fluoroquinolone | Pharmacokinetic parameters for:
|
|||
|---|---|---|---|---|
| Quiescent cells
|
Activated cells
|
|||
| Km (μg/ml) | Vmax (ng/min/106) | Km (μg/ml) | Vmax (ng/min/106) | |
| Ciprofloxacin | 167* (12.2) | 25.2+ (2.64) | 9.76*+ (0.82) | 59.3 (6.39) |
| Norfloxacin | 227* (18.3) | 35.2+ (2.82) | 8.96* (1.43) | 39.7 (4.05) |
| Ofloxacin | 340 (18.6) | 208* (27.1) | NAb | 0 |
| Lomefloxacin | 951 (22.0) | 257* (10.7) | 15.5+ (2.45) | 4.15 (1.03) |
Results are expressed as the means of five determinations, with standard errors of the means listed in parentheses. Within each column, the differences in the mean values are greater than would be expected by chance (P < 0.05, ANOVA). Pairs of identical superscripts within a column denote pairwise comparisons in which the means were not significantly different (P > 0.05, Tukey test). Kinetic analysis of the inducible (PMA-activated) component of ciprofloxacin transport was corrected by subtracting the ciprofloxacin uptake that occurred in quiescent neutrophils from the total uptake observed during the period of assay. The kinetics of ofloxacin transport were similar in quiescent and PMA-activated cells.
NA, not applicable.